Turbine blades (stator blades and rotor blades) used in aircraft engines, industrial gas turbines and other systems are often operated in high-temperature environments for a prolonged time and thus are made of a Ni-based single crystal superalloy that has an excellent heat resistance. The Ni-based single crystal superalloy is produced in the following manner. Al is first added to base Ni to cause Ni3Al to precipitate for precipitation strengthening. High melting point metals, such as Cr, W and Ta, are then added to form an alloy which is formed as a single crystal.
There is known, as such a Ni-based single crystal superalloy, for example, a second generation alloy or the like (for example, CMSX-4 manufactured by Cannon-Muskegon Corporation, PWA1484 manufactured by United Technologies Corporation) in which high-temperature strength, mainly creep strength (also including high-temperature fatigue strength) is enhanced by inclusion of a first generation alloy containing no Re (for example, CMSX-2 manufactured by Cannon-Muskegon Corporation, PWA1480 manufactured by United Technologies Corporation) and 3 wt % of Re. CMSX and PWA are trademarks of alloys.
[Patent Document 1]
U.S. Pat. No. 4,582,548
[Patent Document 2]
U.S. Pat. No. 4,643,782
[Patent Document 3]
Japanese Unexamined Patent Application, First Publication No. Sho 53-146223